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digitalmars.D - Shouldn't c_long and c_ulong be library typedefs?

reply Andrej Mitrovic <andrej.mitrovich gmail.com> writes:
I'm interfacing with C++ and found a little overload problem:

C++:
void test(unsigned int x)  { }
void test(unsigned long x) { }

int main()
{
    unsigned int x;
    unsigned long y;
    test(x);
    test(y);
    return 0;
}

No problem, but in D:

import core.stdc.config;
void test(uint x)  { }
void test(c_ulong x) { }

void main()
{
    uint x;
    c_ulong y;
    test(x);
    test(y);
}

test.d(12): Error: function test.test called with argument types:
	((uint))
matches both:
	test.test(uint x)
and:
	test.test(uint x)

c_ulong is an alias to either uint or ulong based on the architecture.
But it is an *alias*, meaning you can't overload it like the above
based on the architecture. This leads to cases where compiling on one
architecture works (x64 -> c_ulong is D ulong, overloads with uint)
but on another one it doesn't (x32 -> c_ulong is D uint, can't
overload with uint).

Anyway I've two questions:
1) Has anyone come up with a library solution for a typedef because I
need it for cases like these, and
2) Will c_long/c_ulong be converted to a library typedef or will they
remain aliases?
Sep 05 2012
next sibling parent reply "bearophile" <bearophileHUGS lycos.com> writes:
Andrej Mitrovic:


 1) Has anyone come up with a library solution for a typedef 
 because I need it for cases like these, and
 2) Will c_long/c_ulong be converted to a library typedef or 
 will they remain aliases?


In Phobos there is a Typedef, but it's unusable :-(

Bye,
bearophile
Sep 05 2012
next sibling parent Andrej Mitrovic <andrej.mitrovich gmail.com> writes:
On 9/6/12, bearophile <bearophileHUGS lycos.com> wrote:

 In Phobos there is a Typedef, but it's unusable :-(


I forgot to mention, I'm using GDC which is based on 2.059 or earlier,
and which can't compile the Typedef in 2.060 Phobos due to an ICE.

On 9/6/12, Jonathan M Davis <jmdavisProg gmx.com> wrote:

 I'd always expect them to be aliases.
 I'm fairly sure that the C
 linker is going to see any difference between int and long either if long is
 the same size as int


Sorry, I should have been more clear. :)
I'm aware of linker issues but this is handled by uniquely naming
extern(C) functions. Here's an example of how a D virtual would be
invoked:

extern(C) void test__1234_0001(void* d_object, uint* val)
{
    (cast(SomeClass)d_object).test(val);
}

extern(C) void test__1234_0002(void* d_object, c_ulong* val)
{
    (cast(SomeClass)d_object).test(val);
}
Sep 05 2012
prev sibling parent Andrej Mitrovic <andrej.mitrovich gmail.com> writes:
On 9/6/12, Andrej Mitrovic <andrej.mitrovich gmail.com> wrote:

 On 9/6/12, bearophile <bearophileHUGS lycos.com> wrote:

 In Phobos there is a Typedef, but it's unusable :-(


 I forgot to mention, I'm using GDC which is based on 2.059 or earlier,
 and which can't compile the Typedef in 2.060 Phobos due to an ICE.


Anyway here's a temporary workaround:

static import core.stdc.config;
struct c_long
{
    core.stdc.config.c_long val;
    alias val this;
}

struct c_ulong
{
    core.stdc.config.c_ulong val;
    alias val this;
}

I should have posted all of this to D.learn not here, sorry.
Sep 05 2012
prev sibling parent "Mehrdad" <wfunction hotmail.com> writes:
On Wednesday, 5 September 2012 at 23:51:41 UTC, Andrej Mitrovic 
wrote:

 I'm interfacing with C++ and found a little overload problem:

 C++:
 void test(unsigned int x)  { }
 void test(unsigned long x) { }

 int main()
 {
     unsigned int x;
     unsigned long y;
     test(x);
     test(y);
     return 0;
 }

 No problem, but in D:

 import core.stdc.config;
 void test(uint x)  { }
 void test(c_ulong x) { }

 void main()
 {
     uint x;
     c_ulong y;
     test(x);
     test(y);
 }

 test.d(12): Error: function test.test called with argument 
 types:
 	((uint))
 matches both:
 	test.test(uint x)
 and:
 	test.test(uint x)

 c_ulong is an alias to either uint or ulong based on the 
 architecture.
 But it is an *alias*, meaning you can't overload it like the 
 above
 based on the architecture. This leads to cases where compiling 
 on one
 architecture works (x64 -> c_ulong is D ulong, overloads with 
 uint)
 but on another one it doesn't (x32 -> c_ulong is D uint, can't
 overload with uint).

 Anyway I've two questions:
 1) Has anyone come up with a library solution for a typedef 
 because I
 need it for cases like these, and
 2) Will c_long/c_ulong be converted to a library typedef or 
 will they
 remain aliases?




I was complaining about something similar way back when (I was 
saying size_t should not be the same data type as uint) but the 
idea got thrown in the trash.
Sep 05 2012